Water heater with sealed gas burner



Jan. 2, 1968 KEPPEL ET AL 3,361,181

WATER HEATER WITH SEALED GAS BURNER Filed May 5, 1966 mmvmzzs:

ERNST KEPPEL HORST PEICHMANN 131M293, *3 DMM AM United States Patent 3,361,181 WATER HEATER WITH SEALED GAS BURNER Ernst Keppel, Remscheid, and Horst Reichmann, Wuppertal-Elberfeld, Germany, assignors to Job. Vaillant KG, Remscheid, Germany Filed May 5, 1966, Ser. No. 548,362 Claims priority, application Germany, May 13, 1965,

28,467; June 4, 1965, V 28,629

6 Claims. (Cl. 158-1) ABSTRACT THE DISCLOSURE A water heater is provided with a combustion chamber having a stack connection at the top thereof, an oil gasification burner in the combustion chamber, and a power driven blower to supply combustion air to the combustion chamber. The combustion air intake is below the combustion chamber. A jacket is provided around the water heater to define an enclosed air space between the jacket walls and the water heater. Intake air openings are provided at the top of the jacket. Since theremainder of the jacket is sealed the blower intake draws fresh air in through the top intake openings which air circulates down about the water heater inside of the jacket until it reaches a point below the com-bustion chamber, at which time it is drawn into the blower and delivered to the combustion chamber. This flow of air entrains any gaseous products of combustion which might escape from the water heater and returns those products of combustion to the combustion chamber through the blower. s

Background of the invention Known heaters of this variety frequently incorporate an exhaust gas collecting hood for sealingly closing off the upperend of the combustion chamber, and this hood connects to an exhaust gas line. This type of design has the advantage of tight connections between burner and combustion chamber on the one hand and between exhaust gas collecting hood and combustion chamber on the other hand so that neither combustible gases nor exhaust gas may pass into the space surrounding the heater, thereby avoiding the annoyance of smell frequently encountered with oil burners or oil gasification burners. In such oil-heated water heaters it is also known to provide the water heater, including burner and blower, with a tight sheathing into which the required air of combustion is drawn by the blower from below.

However, considerable technical difficulties are encountered in establishing tight connections in such apparatus so that small amounts of combustible gas or exhaust gas will neither accumulate within the sheathing nor escape through its points of connection. It is the-ob ject of this invention to render ineffective the residual combustible gas or exhaust gas escaping fromuntight points of connection internally of the sheathing and to prevent the escape thereof into the surrounding space.

According to the invention this object is accomplished by providing a fresh air inlet gap between the exhaust gas collecting hood and the sheathing. In this manner, the fresh air drawn in by the blower passes outside of the outer surfaces of the combustion chamber and the exhaust gas collecting hood connected therewith and inside of the burner housing enroute to the intake opening of the blower. This fresh air current surrounds the water heater in skirt-like manner and causes all combustible gas or exhaust gas escaping at untight points of connection to be entrained therein. The resulting ourrent of air and entrained gas is then returned to the blower which forces it back into the combustion chamber, thus preventing its escape and the accompanying annoying smell.

The sheathing is suitably provided by a pair of mating sections including a shell-like backwall which carries the water heater, and a front part of shell-type shape having a rim which grips the outer edge of said backw-all. Each shell structure has a cutout portion at the top face and when both are assembled together, these portions form a single opening through which the smaller exhaust gas collecting hood extends, leaving open a fresh air intake gap therebetween.

With a design of the type indicated, the fresh air is supplied to the blower from above, the fresh air current being passed internally of the sheathing past the heat ing section and the burner housing. The drive motor for the blower, being disposed exteriorly of the sheathing, is therefore not affected by the fresh air current. It has already been suggested by others to not only supply fresh air alone to the burner blower, but also hot exhaust gas originating from the flame area of the burner at the same time whereby the blower and the drive motor are both subjected to a thermal load. However, with the herein described system, the drive motor is disposed outwardly of the fresh air current and would not be adequately cooled if thermally loaded.

Therefore, in further modification of the invention, provision must be made to insure that there will be sufficient cooling of the blower drive motor. This is suitably accomplished by using an outside rotor type drive motor for the blower in a wellknown manner. The motors cooling fins are partially embedded in a recess in the sheath ing and covered by a flared out hood which is open at the top thereof in a manner such that cooling air will be circulated by the cooling fins. By embedding the drive motor in a recess of the sheathing, the overall height of the heater is reduced considerably. Although the cooling fins of the outside rotor are effective to cause an air vorticity within the recess, there is insufficient convection away from the recess to properly cool the motor. However, by the arrangement of a flared out hood which is open at the top thereof, the cooling fins are effective to produce a heat-abducting cooling air current.

Summary of the invention This invention relates to a water heater comprising a burner, such as an oil gasification burner, sealingly mounted in a combustion chamber which is supplied with air of combustion by means of a blower.

Brief description 0 the drawings Other objects, advantages and construction features will become apparent from the following description and drawings, wherein:

'FIG. 1 is a schematic representation of the side elevation of a water heater incorporating the principles of the present invention; and

FIG. 2 is a plan view thereof.

Description of the preferred embodiment Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose; as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

Referring to the drawing in more detail, on a room wall 1 there is mounted a back wall 2 of generally shelllike configuration which has an outer edge 2. Mounted to edge 2 is a front section 3, also of shell-like configuration, and having a lip or rim 3 sealingly engaging edge 2'. The apparatus backwall 2 and the front part 3 constitute a tight sheathing for a water heater to be described hereinafter.

The apparatus backwall 2 has attached thereto a combustion chamber surrounded by a coiled tube 4 through which the water to be heated is circulated. The tubes supply and discharge ends 4' (aligned one behind the other in FIG. 1) are sealingly guided through the apparatus backwall 2 at the bottom thereof, one being in threaded engagement with a cold water supply line and the other being in threaded engagement with a warm water discharge line, respectively (not shown). The combustion chamber 5 has sealingly attached thereto the housing 6 of an oil gasification burner as at 7, only the cover plate therefor being shown. The oil gasification burner 7 is supplied by an oil pump 8 via a pressure line 7' which is sealingly guided out of the apparatus front section 3, said pump being connected to an oil supply line 8.

The combustion chamber 5, the upper closure of which is provided by a fin block through which fiow tubes extend, has tightly attached thereto an exhaust gas collecting hood 11 having a fitting or socket 112 formed therewith which connects to an exhaust gas line 13. The apparatus backwall 2 and the front part 3 have cutout portions at the top faces thereof through which the exhaust gas collecting hood 11 extends, leaving open a gap 15 in the sheathing which extends entirely around hood 11. By a blower 9, having two impellers 9' and 9" disposed below the burner housing 6 internally of the sheathing, fresh air is drawn in on the one hand through the annular gap 15 in the direction of the arrow 14, and hot exhaust gas is drawn in one the other hand internally of the burner housing 6 in the direction of the arrow 14. The fresh airexhaust gas mixture is fed into a common chamber 16 by the impellers 9 and 9", and the mixture then passes into a mixing chamber of the burner housing 6 in a manner not shown. Since sections 2 and 3 of the sheathing are tightly connected, the fresh air may only enter through the upper gap 15 and from there passes externally of the exhaust gas collecting hood 11, the combustion chamber 5, and the burner housing 6 therepast to the intake side of the blower 9. If the seal between the exhaust gas collecting hood 11 and the combustion chamber 5 or between the combustion chamber 5 and the burner housing 6 is not tight, so that at the points of connection residual exhaust gas or combustible gas escapes, this gas is returned to the intake side of the blower 9 by the fresh air current and cannot escape into the space surrounding the sheathing. Also, the seal between edge 2 and rim 3' of the sheathing sections is not critical since small amounts of fresh air are sucked in by the blower 9 through any possibly untight points therebetween.

The drive motor 17 of the blower 9 and its outside rotor, the shaft 18 of which extends into the sheathing in sealed manner, are partly disposed in a recess 19 in the lower end of the sheathing. The outside rotor of motor 17 is formed with cooling fins 20 in a well-known manner and is covered by a hood 21. This hood 21 is open at the top thereof and is flared out downwardly and forms an air intake duct between it and recess 19 and an air discharge duct between it and the motor. When the motor 17 is rotated, the cooling fins 20 produce an air flow directed downwardly through the top opening in the flared out hood 21 which passes in the direction of the arrow 22. On the other hand, air is drawn in between the hood 21 and the recess 19 in the sheathing in the direction of the arrow 23 so that the rotating cooling fins 20 are effective to maintain a constant cooling air current in the direction of the arrows 22 and 23, this current abducting heat from motor 17. This cooling air current 22 and 23 is independent of the fresh air current of the blower 9, as indicated by the arrow 14. This additional cooling of the motor 17 is particularly necessary because the blower 9 is strongly heated by the exhaust gas return (arrow 14'), and some of this heat is conducted via the driving shaft 18 to the drive motor 17. By the recessed installation of the drive motor 17 the overall height of the water heater is reduced considerably. Though an air vorticity would be produced in the recess 19 by the cooling fins 20' without the hood 21, it would be impossible to effect a circulation of this type of heat-abducting cooling air current, as shown by arrows 22 and 23.

We claim:

1. In a water heater installation including an oil gasification burner supplied with oil by means of a pump driven by a motor, a blower below said burner and driven by said motor for supplying the air of combustion, a combustion chamber, and an exhaust gas collecting hood sealingly mounted on upper portions of said combustion chamber and adapted for being sealingly connected to an exhaust gas outlet line, means for preventing the escape of gas and fumes outside of said installation, comprising: an outer sheathing having an upper and lower end, said sheathing encasing and sealing said burner, combustion chamber, and blower therein, said sheathing including fresh air inlet means at the top thereof for permitting said blower to draw in fresh air in skirt-like manner within said sheathing and exterior of said combustion chamber en route downwardly to said blower, whereupon said fresh air entrains gas therein from imperfect seals in said installation and conveys same to said blower.

2. An installation as defined in claim 1, wherein said sheathing comprises a pair of hollow shell-like sections, and said fresh air inlet means comprises an opening in the upper end of the sheathing when the sections are assembled, said opening being larger than and surrounding said exhaust gas collecting hood to provide a gap therearound through which fresh air may fiow therein.

3. An installation as defined in claim 1, wherein the lower end of the sheathing includes recessed portions therein, and said motor is disposed outside of said sheathing and includes cooling fins in said recess, said motor and recessed portions being spaced apart and separated by an air circulation hood having an opening at the top thereof for facilitating the circulation of cooling air around said motor.

4. An installation as defined in claim 3, wherein said sheathing comprises a pair of hollow shell-like sections, and said fresh air inlet means comprises an opening in the upper end of the sheathing when the sections are assembled, said opening being larger than and surrounding said exhaust gas collecting hood to provide a gap therearound through which fresh air may flow therein.

5. In a water heater installation including, a furnace comprising a combustion chamber, an exhaust gas collecting hood and an exhaust gas line connection extending outwardly from the chamber, an oil gasification burner in said combustion chamber, a blower supplying combustion air to the burner, and a motor driving the blower, the improvement comprising: an outer sheathing encasing said furnace and blower, said sheathing defining fresh air inlet means about said furnace at the exhaust gas line connection end of the furnace, said sheathing being spaced from the sides of the furnace to define a tubular air space between the furnace and the sheathing, said blower having an air intake at the end of the furnace opposite said exhaust gas line connection whereby when the blower is operating air is drawn in through said air inlet means to said air intake which air flows about the length of the furnace from said connection end to 5 6 said intake and through said air space, and any gas References Cited leakage out of the furnace is entrained in said fresh air to be returned to the furnace. UNITED STATES PATENTS 6. In a water heater installation as set forth in claim 2,223,856 12/1940 Price 122-250 X 5, wherein said motor is outside said sheathing, and in- 5 3 192 986 7/ 196,5 Haag 158 4 cluding air circulation means for the motor including an air intake duct between the sheathing and the motor 3301305 1/1967 Klmmel 158-45 and an air discharge duct between the motor and the FREDERICK L MATTESON JR Primary Examiner air intake duct, and means connected to the motor to produce air flow through aid du t E. G. FAVORS, Assistant Examiner. 

